Turbochargers are used with engines to improve the engine's volumetric efficiency. Turbochargers, as well as other types of turbomachinery, include high speed rotating components, which generally require damping provisions. In performance turbocharger applications, where rotor shaft speeds are high and external influences on shaft motion are also high, the ability to effectively dampen the rotor shaft has a close relationship to the performance of the engine as a whole. Rotor bearing devices of the turbomachinery are typically located adjacent to the rotor shaft to dampen the rotor shaft relative to the turbomachinery housing.
Up until now, the systems used to locate the rotor bearing device of the turbomachinery relative to the turbomachinery's housing to assist in damping the shaft have failed to precisely locate the bearing device. In particular, the current systems fail to substantially limit the bearing device from surging and rolling while allowing for the required, remaining freedoms of motion, namely heaving, swaying, pitching, and yawing. For example, in one prior art system, a cylindrical, knurled pin is positioned within a clearance fit hole in a bearing device to locate the bearing relative to the housing. Unfortunately, the knurled pin must be loosely fitted within the bearing device to allow for the required freedoms of motion for the bearing device. Because of the loose fit of the knurled pin within the bearing device, the prior art system has failed to precisely locate the bearing device so as to substantially limit the bearing device from surging and rolling. The loose fit of the knurled pin also results in diminished performance and causes the shaft and bearing device to wear quickly.
Accordingly, there exists a need for an assembly that can precisely locate the rotor bearing system so as to substantially limit the bearing system from surging and rolling while allowing for a film of oil or the like to dampen the required four remaining freedoms of motion of the rotor bearing system. The assembly should also afford the benefits of increased performance of the turbocharger and a longer life span for the turbocharger.